1. Field of the Invention
The present invention relates to an optical disc of write-once type, such as a Blu-ray Disc Write Once (BD-WO), and a method and apparatus for managing a defective area on the write-once type optical disc.
2. Background of the Related Art
A new type of high density optical disc such as a Blu-ray Disc Rewritable (BD-RE) is being developed. A benefit of the BD-RE is that it has a rewritable capability where the quality video and audio data can be written, erased and rewritten thereon repeatedly.
FIG. 1 is a block diagram of a general optical disc device for writing/reproducing data to/from an optical disc such as a BD-RE. As shown in FIG. 1, the optical disc device includes an optical pickup 11 for recording/reproducing a signal to/from a BD-RE 10, a video disc recorder (VDR) system 12 for processing a signal from the optical pickup 11 as a reproduced signal, or demodulating and processing an external data stream into a writable signal suitable for writing onto the BD-RE 10, and an encoder 13 for encoding an external analog signal and providing the encoded signal to the VDR system 12.
FIG. 2 shows a structure of a related art BD-RE. Referring to FIG. 2, the BD-RE is divided into a Lead-In Area (LIA), a data area, and a Lead-Out area (LOA), with an Inner Spare Area (ISA) and an Outer Spare Area (OSA) assigned to a fore end and a rear end of the data area.
Referring to FIGS. 1 and 2, the VDR system 12 of the optical disc device writes in the data area of the BD-RE the external data in clusters corresponding to an ECC block unit having a predetermined size of recording, after the VDR system 12 encodes and demodulates the external signal into a signal suitable for writing. During the writing process, if there is a defective area found in the data area of the BD-RE, the VDR system 12 carries out a series of replacement writing operations in which the clusters of data written onto the defective area is written onto one of the spare areas, e.g., on the ISA in place of the defective area. Therefore, even if there is a defective area in the data area of the BD-RE, the VDR system 12 can prevent a data writing error in advance by writing the clusters of data written in the defective area onto the spare area.
A Blu-ray Disc Write-Once (BD-WO) is another type of high density optical disc that is being developed where a high quality of data can be recorded and reproduced to/from the disc. As the name may suggest, data can be written only once on the BD-WO and is not rewritable on the BD-WO, but the BD-WO can be read repeatedly. As a result, the BD-WO is useful where the rewritability of data on a recording medium is not desired.
Unfortunately, since the BD-WO is still in the early development stage, there are no schemes, no disc structures, no apparatuses and no methods on how to manage the defective areas of the BD-WO, which will be needed for the BD-WO to be commercially viable and operationally feasible.